Syringe



Dec. 2, 1958' c. "M. HARDEN I SYRINGE Filed Dec. 5, 1955 nllllnlllirllll INVENTOR. 64/22 M. #41205- uum mm United States Patent 2,862,494 SYRINGE V 7 ar Har en Whi ie Calif- Application December 5,1955, Serial No. 551,029 7 Claims. (Cl. 128 -218) This invention relates to a syringe, andmore particularly to a syringe designed especially for injection of a measured, but small quantity .of medicament. However, the invention notlimited to such small dosages and can be applied tolarger sizesiif desired.

The invention further relates to .a disposable type syringe designed to, be inexpensive enough to permit it to be discarded after a single use. This feature permits the syringe of, this invention to be used as a package holding at single dose, completely sterilized and ready for use without further handling.

It isa feature of this invention that the syringe is nr r ed th aba s h vin a bottom n n a aaaula ener ies .su s an iallrrara l he o but actuall ta ery sm l aa tsang e er n is also p vided with a barrel or cylinder extending substantially perpendicular to the bottom of said base. Said cylinder houses a piston which thus reeiprocates substantially perpendicular to said base bottom.

It is therefore an object of this invention to provide a syr ng 2 13. 19 of. immune ery ma lp s a smal a v 0. 1 1 =ubl entimeter. assur te ymet r It is another object of .th' nvention. to provide such a syringe adjustable as to volume of fill, without the introduction. of any entrapped airl-t isaifurther-obj-ect.ofthis invention to provide such a syringe in;.which-the..axis.alongwhich the..needle is injected into the patient is substantially perpendicular to the stroke of the medicament-expelling plunger.

It is another object of this invention to provide a syringe having all the objects and features stated but which is still very inexpensive to make in large quantities, enabling the same to be discarded after a single use.

These and other objects, features and advantages will be apparent from the annexed specification in which:

Figure l is a perspective elevation of a syringe embodying the present invention;

Figure 2 is a section taken along the line 2--2 of Figure 1;

Figure 3 is an enlarged fragmentary section similar to Figure 2; and

Figure 4 is an enlarged fragmentary section taken along the line 44 of Figure 2.

Figure 5 illustrates an alternative form of cannula which can be used in connection with the syringe of this invention.

Referring now more particularly to the drawings, the syringe illustrated comprises four basic component parts: The body 10, the plunger or piston 11, the cannula or needle 12 and the needle sheath 13. All of these parts with the exception of the cannula 12 are preferably molded of polyethylene plastic.

The body includes a base 14, an upwardly extending portion 15 which is cored as at 16 to provide a cylinder 17, and a rearwardly extending channel-shaped portion 18, the downwardly extending flanges 19 of which have edges co-planar with the fiat bottom of base 14. The body 10 is also provided with a forwardly extending "ice cylindrical boss 20. The boss 20 may be provided with an annular recess 21 and a slot 22 may be moulded into the body 10 in the bottom wall of cylinder 17 as best seen in Figure 4.

Plunger or pistonll is a solid cylindrical member of polyethylene plastic having a pair of ribs 23 and 24 moulded thereon which have an outer diameter slightly greater than the internal diameter ofthe bore 16 This assures elfective sealing of the piston 11 in cylinder 17.

Obviously, however, the ribs 23 and 24 may be formed separately and the 0 rings sealed in semi-circular annular grooves in the piston 11.

While as stated above, it is preferred to form all parts of the syringe except the cannula, which is preferably of stainless steel, of polyethylene plastic, it has. been'found that the piston 11 may be formed of rubber or neoprene.

The cannula 12 is preferably formed with a closed pointed end 25 adjacent which is an upwardly facing slot 26. The cannulais provided with a conventional pointed end .27, the bevel of which is upon the upper side of the cannula. The cannula 12 when properly insertedin the body 10, lies at a very small acute angle to the bottom of base 14 and fianges 19 v so that thetip of the pointed end 27 is substantially corplanar with the bottom of base 14.

Thecannula 12 is preferably inserted in the body 16 as follows: The.cannula is forcibly driven through the boss 20 and the base 14 until the closed end 25 emerges into the slot 22 and finally imbeds in the body 14 as best shown in Figures 2 and 4. Turning the cannula as if in a lathe will facilitate driving, thecahnula through the materialofbosslll and body 14, during the course of which t sed 1 5.n e 1y make an p si e m terial and then stretches thesame so that. whenrfully in place, the cannula is securely held in the material under hoop tension.

Referring now more particularly to Figure, 5, there is shown an alternativeform of cannula ,12-A. Asoriginally specified, this alternative form is a conventional annu ai eve ed, an sha pe ed a both. nd at .7,A and.. B.- H w ve pr to u e, he. inne n r e over as at 30 to provide a substantially closed end which may be driven through the body of the flange and form the same function as the closed end 25 of the previous embodiment; that is, it prevents the picking up of a core of plastic in the cannula as it is driven into position, the bevelled end 27-B in this case forming the same function as the opening 26 in the previous embodiment.

The sheath 13 is a conical-shaped member, the hollow 28 of which tapers to an end 29 having an inner diameter slightly less than the outer diameter of the cannula 12, thus providing a press fit for the tip of the cannula and securely sealing the same when in place. The other end of the sheath 13 may be provided with an inwardly extending annular ring 30 adapted to seat in the recess 21, although it has been found that both recess 21 and ring 31 may be eliminated and the inner diameter of the open end of the sheath 13 may be made slightly smaller than the outer diameter of the boss 20 to again provide a seal with a press fit.

The syringe of this invention lends itself to several modes of filling. First, the piston 11 may be removed and the cylinder 17 filled directly; air being excluded on return of the piston 11 in the conventional manner. Secondly, the piston 11 may be driven completely home, the tip 27 of the cannula 12 inserted in the medicament and the piston 11 then withdrawn, thus sucking the medicament into cylinder 17. Lastly, the piston 11 may be driven home, the cannula inserted in a body of medicament, pressure applied to this body thus forcing medicament into the cannula and cylinder and forcing piston 11 upwardly until its top engages a pre-set stop. In this manner, an accurately gauged fill is assured and a negligible amount of air is entrapped.

In the use of the syringe of the present invention, the operator selects a prefilled syringe, removes sheath'13 and places the syringe upon the skin of a patient with the flat bottom of base 14 and flanges 19 as well as the tip 27 engaging the skin. A forward movement of the syringe then causes the tip of the cannula to be driven into the skin, preferably intradermally. With the syringe thus located, depressing the piston 11 then injects the measured doses of medicament. It will be noted that the force applied in injecting the cannula and that applied in injecting the medicament are substantially mutually perpendicular.

Where there has been described what is at present considered the preferred embodiment of the invention, it will be understood that various changes and alterations may be made therein without departing from the essence of the invention, and it is intended to cover herein all such changes and alterations as come within the true scope and spirit of the annexed claims.

I claim:

1. A hypodermic syringe comprising: A body formed of injectable plastic material and having a substantially flat skin contacting base; a cannula mounted in said body and extending forwardly therefrom at a small acute angle to said base, said cannula having a pointed end, the tip of which lies substantially in the plane of said base; a cylinder in said body extending substantially perpendicular to said base; a piston in said cylinder; said cannula extending into said cylinder and having an opening communicating with said cylinder.

2. A hypodermic syringe comprising a body, said body being formed of resilient resinous material, a cannula extending from said body, a chamber in said body, said cannula communicating with said chamber, the inner end of said cannula being bevelled and curled backward to form a closed end on said cannula and an opening in said cannula adjacent its end for communicating with said chamber. a

3. A hypodermic syringe comprising a body; a cannula mounted in said body and extending outwardly therefrom; a cylinder in said body; a piston in said cylinder, said cannula extending into said cylinder and having 4 an opening communicating with said cylinder; said cylinder being disposed substantially perpendicular to said cannula; said cannula having a closed pointed inner end imbedded in said body and an upwardly facing slot forming said opening.

4. A hypodermic syringe comprising a body; a cannula mounted in said body and extending outwardly therefrom; a cylinder in said body; a piston in said cylinder, said cannula communicating with said cylinder; said cylinder being disposed substantially perpendicular to said cannula; said cannula being bevelled at its inner end to form an opening therein, the tip of said inner end being curved backward towards said opening.

5. A hypodermic syringe comprising a body; a cannula mounted in said body and extending outwardly therefrom; a cylinder in said body; a piston in said cylinder, said cannula extending into said cylinder and having an opening communicating with said cylinder; said cylinder being disposed substantially perpendicular to said cannula; said body being provided with a groove in the bottom wall of said cylinder; said cannula having its portion adjacent said opening seated in said groove; said body being provided with a forwardly extending boss surrounding a portion of said cannula and a hollow tapered sheath seated on said boss and surrounding said cannula.

6. A syringe as set forth in claim 5 in which the hollow of said sheath tapers to an internal diameter less than the outer diameter of said cannula.

7. A syringe as set forth in claim 6 in which said boss is provided with an annular recess and the open end of said sheath is provided with an inwardly extending flange, seated when said sheath is in place in said recess.

References Cited in the file of this patent UNITED STATES PATENTS 2,392,196 Smith Jan. 1, 1946 2,605,765 Kollsman Aug. 5, 1952 FOREIGN PATENTS 28,464 Sweden Mar. 5, 1910 497,017 Belgium July 31, 1950 806,702 Germany June 18, 1951 

